KR20130140793A - Engine exhaust gas additive storage tank - Google Patents

Abstract

A tank for storing a liquid additive for an internal combustion engine exhaust gas, the tank being capable of connecting the electric component to a wall forming an inner volume, an electrical component 3 located in the inner volume, and a voltage source outside the tank. At least one of the electrical cables is inserted into an intermediate portion 6 connected to a base plate 1 mounted in an opening formed in the wall of the tank, the base plate being casing The casing is mounted in a leakproof manner around an orifice formed in the base plate, the intermediate part is fastened by a quick connect coupling to the casing, the casing also includes an electrical connector 11, and the electrical cable is sealed With the help of (7) it is connected to the electrical connector in a leakproof manner, which is connected to the outside of the tank from the orifice at the base plate. Said, the seal is inserted in such a way to be inserted between the intermediate portion and the electrical connector portion and an intermediate housing 8 is inserted into any one method or mode of insertion both of the manner in which the insert.

Description

ENGINE EXHAUST GAS ADDITIVE STORAGE TANK}

The present invention relates to an additive storage tank for engine exhaust gas.

Regulatory laws on vehicle and truck emissions focus, among other things, on reducing emissions of NOx to the atmosphere. One known method to achieve this purpose of reducing emissions is to use the Selective Catalytic Reduction (SCR) method, which can reduce nitrogen oxides by injecting a reducing agent, usually ammonia, into the exhaust passage. . This ammonia can be derived from pyrolytic decomposition of the ammonia precursor solution, where the concentration of the ammonia precursor solution becomes the eutectic concentration. Such ammonia precursors are generally urea solutions.

In the SCR process, the high concentrations of NOx produced by the engine during combustion at optimum efficiency exit the engine and are processed in catalytic converters. This treatment requires the use of the highest quality and precise concentration of reducing agent. Thus, the working solution is precisely metered and injected into the exhaust stream, where the working solution is hydrolyzed before converting the nitrogen oxides (NOx) into nitrogen (N ₂ ) and water (H ₂ 0).

In order to carry out this process, it is necessary to install a tank in the vehicle containing the additive (generally urea) solution and also a device for weighing and injecting the target amount of the additive into the exhaust passage.

In order to correctly meter the additive solution injected into the exhaust gas, electrical components such as level gauges, temperature sensors, quality sensors, resistance heating elements and the like are generally incorporated in the additive tank. These parts require wires connected to one (or more) wiring harness or one (or more) other parts of the vehicle or SCR system located outside the additive tank, which results in a number of problems. Have. First, the additive solution is generally corrosive, and standard conductive materials have no or no corrosion resistance to it. Next, if the track is coming out of the tank, leaktightness should be maintained, which can also cause problems, especially in the long term.

Application WO 2008/138757 proposes a number of techniques for connecting a track through a cover of its heated vortex port in a urea tank, where the track passes through the cover with a seal installed, the seal being elastic It is in the form of a plug and is leak-proof and inserted into the housing of the cover.

In all the techniques described in the prior patent document, the leakage preventing function is maintained due to the following configuration: using one or more seals (symbol "30" in the drawing); Vulcanizing the seal directly to the cable or a member for tensioning the seal around the cable (reference numeral “38” in the drawing); And a holder bolted to the cover (symbol "34" in the figure). Thus, such an assembly is relatively complex and expensive.

In one variant (modification of FIG. 5), two cables each provided with an O-ring 30 are mounted to the intermediate portion 39, and are themselves mounted to the cover with the aid of the seal 43. This technique is not intended to be permanently immersed in aqueous urea solution additive solutions. That is, the portion between the O-ring 43 and the tank inner portion does not have a leakage preventing function. With the advent of the icing / thawing cycle, the expansion of the additive between the intermediate portion and the housing results in a loss of the leakproofing of the assembly and / or damage to the assembly. In addition, the two seals 30 around the cable of the heater are not blocked from the outside by the intermediate portion. In contrast, the seal is exposed to the outside environment and supported only at the center of the intermediate portion 39. This configuration causes a loss of leakage protection, especially in submerged. In addition, when two wires come out of the tank through the seal, these two wires must be electrically connected to the voltage source carefully when trying to mount the tank in the vehicle.

The patent EP 2029865 in the name of the applicant proposes a base plate which precisely comprises a vortex port which is immersed, ie mounted through an opening formed in the bottom wall of the tank. In order to heat the tank, in particular for the elements contained in the vortex pot, this base plate is preferably also the heating element described in the above-mentioned publication WO'757, and preferably also in the name of the present applicant and the contents thereof. It is equipped with the flexible heater described in WO 2008/138960, which is incorporated by reference.

In this technique, the electrical connection (electrical connection not only of the heating element but also of the other electrical components listed above) must be carried out through the opening of the submerged base plate made of plastic, preferably by injection molding.

The technical idea (object) of the present invention is to provide a fastening system described in patent application WO'757 compatible with the immersion type technique and at the same time simplify this configuration. This object is achieved by securing a configuration that prevents the sealing portion and the wiring from coming out of the tank because the casing uses a casing which easily mounts the pre-assembled connection assembly in a leakproof manner by a simple quick connect coupling.

Accordingly, the present invention relates to a tank for storing a liquid additive for an internal combustion engine exhaust gas, wherein the tank comprises a wall forming an inner volume, an electrical component located in the inner volume, and a voltage source outside the tank. At least one electrical cable that makes it possible to connect parts, wherein at least some of the electrical cable is inserted in an intermediate portion connected to a base plate mounted in an opening formed in the wall of the tank. According to the invention, the base plate has a built-in casing, the casing is mounted in a leak-proof manner around the orifice formed in the base plate, the intermediate portion is fastened by the quick connect coupling to the casing, the casing is Also included is an electrical connector, wherein the electrical cable is connected to the electrical connector in a leakproof manner with the aid of a seal, the electrical connector coming out of the tank from an orifice in the base plate.

The additive of the present invention is preferably a reducing agent capable of reducing NOx present in the exhaust gas of the internal combustion engine. This reducing agent is advantageously an ammonia precursor in an aqueous solution. The present invention provides good results when the aqueous urea solution is a eutectic / urea solution, in particular an urea content between 31.8% and 33.2% by weight, such as an AdBlue ^® solution containing about 18% ammonia. The invention is also applicable to also urea / ammonium formate mixtures in aqueous solution is commercially available under the trademark Denoxium ^® and containing about 13% ammonia. The latter has an advantage over urea only if it is constantly frozen from -35 ° C (as opposed to -11 ° C) and has a disadvantage in the corrosion problem associated with the release of formic acid.

The present invention can be applied to any internal combustion engine that is easy to generate NOx in the exhaust gas. Such an internal combustion engine is an engine with or without a fuel return passage (i.e., a passage for returning excess fuel not consumed by the engine to the fuel tank). The invention is advantageously applied to diesel engines, in particular vehicle diesel engines, particularly preferably for truck diesel engines.

The tank according to the invention comprises a wall made of any material, preferably a material that is chemically resistant to the additive. Typically such materials are metal or plastic. In the case of urea, polyolefin resins, in particular polyethylene (and more particularly HDPE or high density polyethylene), polyamides (PAs) and also polyacetals, and in particular POM (polyoxymethylene) constitute the preferred materials. The same materials as these may also be used for the leak-proof casing, the base plate, and / or the intermediate part of the tank according to the invention. Polyamides (PAs) are particularly suitable for these parts, in particular PA-6,6.

According to the invention, the wall of the tank comprises at least one opening, on which a base plate comprising an orifice is mounted, and a casing is mounted around the orifice in a leakproof manner.

The expression “base plate” includes a mounting plate or flattened portion (ie, its thickness is much smaller than other dimensions (eg, at least 5 or 10 times smaller) and substantially flat), which portion is It is meant to have a use for closing an opening formed in the wall, preferably in the upper or lower part thereof (referred to as the upper wall and the lower wall, respectively). In the latter preferred embodiment, the base plate may extend into the tank through a chamber or hollow, the chamber or hollow being through the tank through at least one orifice through which the additive can circulate. It can also communicate with and act as a swirl pot. Preferably, the casing according to the invention is molded integrally with the base, preferably injection molded. However, the casing may be closed by a separately mounted cover.

The expression "bottom wall" means substantially the lower half of the tank when the tank is mounted on the vehicle (half, regardless of whether the tank is molded in one piece (in one piece) or from two part sheets or cuts). ).

The base plate according to this embodiment (variation) is particularly suitable for supporting parts which pass through the tank wall and / or are located inside the tank. The base plate has a self-closing perimeter of any shape, the perimeter of which is generally circular.

Preferably, the electronic component at least partly disposed in the tank according to the invention is selected from the following elements: level gauge, temperature sensor, quality sensor, pressure sensor, pressure regulator, heating element. These elements (or members) are embedded in the swirl pot of the tank. As is the case with heating elements, for example in general, the invention is particularly useful when the parts comprise two cables. The present invention has been successfully applied to flexible heaters as described above.

The electrical cable of the electronic component must include a coating that has corrosion resistance to corrosion by additives and / or provides such resistance (corrosion resistance) to the assembly. Good results were obtained with the silicone coated cable. Similarly, good results with metal cables (preferably made of stainless steel) coated with fluoropolymers (eg PFA or perfluoroalkoxy) and preferably coated (eg silicon) Obtained.

 The intermediate part according to the invention is a hollow part, ie comprises at least one housing for the cable and its seal, if necessary, and is generally cylindrical.

According to the invention, the electrical cable (s) must be capable of connecting electrical components to a voltage source, the cables being connected to electrical connectors, at least a portion of these electrical connectors being also located in the leakproof casing and at least partially in the leakproof casing. The connector complementary to the integrally formed portion further facilitates connection to the voltage source.

The connector according to the invention is also preferably made of PA-6,6 and preferably reinforced with, for example, glass fiber, which gives practically good results.

The cable (s) are preferably pressed into the contacts which (are themselves) fastened to the electrical connectors. The connector is preferably almost entirely embedded in the leak-proof casing (hence only the part for connecting to the complementary connector emerges from the tank).

The connection to the voltage source consists of an electronic casing incorporating a complementary connector and preferably an electronic control unit (or ECU) for the component.

The seal for securing the leakage preventing function between the connector and the cable is inserted in any one of the manner of being inserted between the intermediate part and the electrical connector and the method of being inserted into the housing of the intermediate part or both. Preferably, the seal is inserted between the intermediate part and the connector or in the housing of the intermediate part. In the case of the manner of insertion into the housing of the intermediate part, it is therefore preferable to use a complementary seal for connecting the intermediate part to the casing in a leakproof manner. Thus, this complementary seal is preferred because it includes substantially two folded seals. Regardless of the embodiment (variation), the seal or seals are preferably made of an elastic material such as EPDM or silicone, with silicone being more preferred.

The seal offers a good result, the seal being marketed as a "single wire seal" (name) by Tyco Corporation, in particular the middle part comprising two housings for two cables, each housing The embodiment (modification) in which the seal is provided provides good results. These seals include corrugated (ringed) portions to provide specific movement / axial flexibility, and provide straight portions for forcing onto the relief. In this embodiment (variant) it is advantageous to remove the part used for forcing mounting from the seal (to obtain the height space and reduce the dimensions of the parts), but from the point of view of the invention this part This is not necessarily used.

According to the invention, the base plate incorporates a casing. The term "internal" means that the casing is fastened to the periphery of the orifice (by welding, gluing, mechanical fastening, etc.) or molded together from a single part. Preference is given to molding together from a single part, in particular for base plates made of plastic.

The casing according to the invention is, by definition, a hollow part, which, among other things, accommodates the intermediate part and has a size and shape such that the intermediate part can be attached by a quick connect coupling. The expression “quick connection coupling” means forcing contact of one (side) portion with the other (side) portion which does not necessarily require a complementary portion to hold the assembly together. Common examples of this type of connection include "fir-tree" connections, "quick-connect" connections, and reliefs suitable for simple clip fastening.

Therefore, for this purpose, it is preferable that the intermediate portion is provided with a quick-fastening relief in a complementary relationship with the corresponding relief in the casing. Grooves on the outer surface of the intermediate portion and complementary channels on the inner surface of the casing can provide effective clip fastening.

The present invention also relates to a base plate for a tank as described above, for which purpose the base plate has a built-in casing, which is mounted in a leak-proof manner around an orifice formed in the base plate, and has an appropriate dimension and shape. The intermediate part can be fastened via a quick connect coupling and is also configured to receive the electrical connector.

The invention also relates to a method for connecting electrical components of a tank for storing liquid additives for internal combustion engine exhaust gases with the aid of electrical cables and through base plates mounted in openings in the walls of the tank to voltage sources outside the tank. As one, according to this method:

Inserting at least one part of the electrical cable into the intermediate part;

Connecting the cable to the electrical connector with the help of the seal;

Inserting the assembly into a casing mounted in a leakproof manner around an orifice of the base plate and fastening the intermediate portion to the casing with a quick connect coupling so that the connector emerges out of the tank from an orifice formed in the base plate. It includes; to.

In this way, an electrical cable / intermediate / connector assembly may be connected to the electrical component prior to mounting the electronic component in the tank, which makes the assembly and connection of the assembly particularly easy for the manufacturer of the tank.

The present invention is illustrated in the accompanying drawings, respectively, as shown in FIGS. 1 to 6 as follows, but the present invention is not limited thereto.
1 is a cross-sectional view of a tank's base plate along a vertical central plane according to a variant of the invention (one embodiment).
FIG. 2 is a cross-sectional view of the base plate shown in FIG. 1 in which a leak-proof casing is taken along a vertical central plane. FIG.
FIG. 3 is a cross-sectional view of the base plate shown in FIG. 1, taken along a vertical center surface of the leak-proof casing.
FIG. 4 is a three-dimensional enlarged front view of an intermediate part included in the leak-proof casing shown in FIG. 3.
5 is a top view of the same intermediate portion.
FIG. 6 shows how the system illustrated in FIGS. 3-5 is preferably modified to reduce its vertical space requirements.

1 shows a heater 3 of the flexible type (ie at least one resistive track inserted between two flexible films or fixed to a flexible film, preferably made of silicon), The heater 3 is mounted to the base plate 1. The base plate 1 is for immersing in the tank, i.e. closing the opening (not shown) formed in the bottom wall of this tank. The heater 3 is supplied with power through two cables 4, the two ends of the cable being welded to the ends of the resistance tracks of the heater, and thus the weld is covered by the patch 5, the patch 5 ) Is also preferably made of silicone. Both ends of these cables are connected to the electrical connector, but are not shown in FIG. 1, but are included in the leak-proof casing 2 integrally formed with the base plate.

FIG. 2 [sectional drawing taken along the center plane of the modification (one embodiment) of the casing 2] shows the intermediate part 6 by which the part of the cable 4 of the heater 3 was clip-fastened to the said casing 2. Is inserted with the aid of the groove 10, where the groove 10 acts with a complementary channel in the casing 2 to provide a quick connect coupling, and the leakage preventing function of the coupling It is secured by the sealing part 7 forcibly mounted to the casing 2, and at the same time, the leakage preventing function regarding the coupling between the cable 7 and the electrical connector 11 is secured.

3 (sectional view taken along the vertical intermediate plane of another variant of the casing 2), in this case, the intermediate part 6 in which the housings 8 for the two sealing parts of the "single wiring sealing" type are installed is provided with a groove 10. It is shown how the clip is fastened to the casing 2 with the aid of which the groove 10 acts with a complementary channel in the casing 2 to provide a quick connect coupling, the leakage preventing function of the coupling being It is secured by the O ring 9 accommodated in the groove of the intermediate part 6.

The geometry of the intermediate part 6 is illustrated in FIGS. 4 (front view) and 5 (top view). In FIG. 5 (a slightly eccentric view), an orifice through the seal 7 'can be seen for the purpose of passing the cable.

FIG. 6 shows a more compact (short) view as shown in the right view by removing a portion of the seal (the border delineated by 7 "in the left figure) (not required for this application) for forcing the seal 7 in a particular application. ) Shows how to provide a version.

In the drawings, the dimensions are for illustration, and like numerals denote like parts, ie:
1. Immersion base plate for tank for aqueous urea solution
2. Leak-proof casing
3. flexible heater
4. Electric cable to power the heater
5 Patch covering the weld of the cable to the heater
6. Middle part
7. Flexible seal
7 '. "Single wire seal" type seal
8. Seals and housings for cables
9. O ring
10. Grooving Clip
11. Electrical connector

Claims (13)

A tank for storing a liquid additive for an internal combustion engine exhaust gas, the tank being capable of connecting the electric component to a wall forming an inner volume, an electrical component located in the inner volume, and a voltage source outside the tank. At least a portion of the electrical cable is inserted into an intermediate portion connected to a base plate mounted in an opening formed in the wall of the tank, the base plate having a casing, the casing being It is mounted in a leakproof manner around an orifice formed in the base plate, the intermediate part is fastened to the casing by a quick connect coupling, the casing also includes an electrical connector, and the electrical cable is leakproof with the aid of a seal. The electrical connector in such a way that the electrical connector Coming out of the tank from an orifice in the base plate, and the seal is inserted in any one of the manner of being inserted between the intermediate part and the electrical connector and the method of being inserted into the housing of the intermediate part or both. Characterized in that
Tank for storing liquid additives for internal combustion engine exhaust gases. The method of claim 1,
The opening is closed by the base plate and located on the bottom wall of the tank, the base plate extending through the chamber or the hollow into the tank, the chamber or the hollow being at least one through which the additive can circulate. It is in communication with the tank through an orifice, characterized in that acting as a swirl pot (swirl pot)
Tank for storing liquid additives for internal combustion engine exhaust gases. 3. The method according to claim 1 or 2,
The casing is formed integrally with the base, characterized in that
Tank for storing liquid additives for internal combustion engine exhaust gases. 4. The method according to any one of claims 1 to 3,
The electrical component is characterized in that the flexible heater
Tank for storing liquid additives for internal combustion engine exhaust gases. 5. The method according to any one of claims 1 to 4,
The cable is coated with a fluoropolymer as a stainless steel cable, and a silicone resin coating is formed.
Tank for storing liquid additives for internal combustion engine exhaust gases. The method according to any one of claims 1 to 5,
Connection to said voltage source is made by means of a connector complementary to a portion formed at least partially integrally with said leak-proof casing
Tank for storing liquid additives for internal combustion engine exhaust gases. 7. The method according to any one of claims 1 to 6,
The cable is crimped to an electrical contact of the connector
Tank for storing liquid additives for internal combustion engine exhaust gases. 8. The method according to any one of claims 1 to 7,
And a complementary seal for connecting the intermediate part to the casing in a leakproof manner.
Tank for storing liquid additives for internal combustion engine exhaust gases. The method according to any one of claims 1 to 8,
The intermediate part includes two housings for two cables each provided with a sealing part including a pleat (ring) part.
Tank for storing liquid additives for internal combustion engine exhaust gases. 10. The method according to any one of claims 1 to 9,
The quick connect coupling is a clip fastening comprising a groove formed on an outer surface of the intermediate portion and a complementary channel formed on an inner surface of the casing.
Tank for storing liquid additives for internal combustion engine exhaust gases. A base plate for a tank according to any one of claims 1 to 10,
The base plate incorporates a casing, the casing is mounted in a leakproof manner around an orifice formed in the base plate, has an appropriate dimension and shape so that an intermediate portion can be fastened through a quick connect coupling, and the electrical connector Characterized in that
Base plate for the tank. A tank manufacturing method for manufacturing a tank according to any one of claims 1 to 10,
Inserting at least one portion of said electrical cable in the middle;
Connecting the cable to the electrical connector in a leakproof manner with the aid of a seal;
Inserting the assembly into the casing and fastening the intermediate portion to the casing with a quick connect coupling such that the connector exits the tank from an orifice formed in the base plate;
≪ RTI ID = 0.0 >
Tank manufacturing method. The method of claim 12,
An electrical cable / intermediate / connector assembly is connected to the electrical component prior to mounting the electronic component in the tank.
Tank manufacturing method.

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